"""Privacy utilities: pseudonym manager, simple commitments, privacy layer placeholder."""
import time
import hashlib
from typing import Dict, Any
from dataclasses import dataclass

class PseudonymManager:
    def __init__(self, rotation_interval: float = 60.0):
        self.rotation_interval = rotation_interval
        self._store: Dict[str, str] = {}
        self._timestamps: Dict[str, float] = {}

    def rotate_pseudonym(self, vehicle_id: str) -> str:
        pseudonym = hashlib.sha256(f"{vehicle_id}-{time.time()}".encode()).hexdigest()[:16]
        self._store[vehicle_id] = pseudonym
        self._timestamps[vehicle_id] = time.time()
        return pseudonym

    def get_current_pseudonym(self, vehicle_id: str) -> str:
        now = time.time()
        if (vehicle_id not in self._store) or (now - self._timestamps.get(vehicle_id, 0) > self.rotation_interval):
            return self.rotate_pseudonym(vehicle_id)
        return self._store[vehicle_id]

# Simple hash-based commitment (Pedersen placeholder)
def commit(value: bytes, blinding: bytes) -> str:
    return hashlib.sha256(b"C" + value + blinding).hexdigest()

def verify_commit(commitment: str, value: bytes, blinding: bytes) -> bool:
    return commitment == commit(value, blinding)

@dataclass
class PrivacyWrappedMessage:
    payload: bytes
    commitment: str
    pseudonym: str
    zk_proof: bytes = b"ZK-PROOF-PLACEHOLDER"

class PrivacyLayer:
    def __init__(self, pseudonym_manager: PseudonymManager):
        self.pm = pseudonym_manager

    def wrap(self, vehicle_id: str, payload: bytes, include_commitment: bool = True, include_zk: bool = False) -> PrivacyWrappedMessage:
        pseudo = self.pm.get_current_pseudonym(vehicle_id)
        blinding = hashlib.sha256(pseudo.encode()).digest()[:16]
        if include_commitment:
            c = commit(payload, blinding)
        else:
            c = ''
        zk = b'' if not include_zk else b'ZK-PROOF-PLACEHOLDER'
        return PrivacyWrappedMessage(payload=payload, commitment=c, pseudonym=pseudo, zk_proof=zk)
